Summary OCR A-Level Biology 5.6.2 Chloroplast Structure

Chloroplast Structure
Inter-
membrane Granum
Outer
Space
Membrane
Lamellae
Inner
Membrane




Starch
Grain




Ribosome
Stroma
Thylakoid DNA
Space Lipid Globule
Thylakoid
Membrane




Photosynthetic Pigments
 There are light-harvesting funnels in the thylakoid membrane from the stroma to the
thylakoid space
 Pigments at the end of these funnels are arranged in light-harvesting clusters called
photosystems
 Many accessory pigments surround a primary pigment – accessory pigments pass
energy form absorbed light onto the primary pigments (which act as reaction centres)
 Primary pigments can only absorb certain wavelengths of light so accessory pigments
help harvest energy from other wavelengths
 Photosystem I – chlorophyll a P700
 Photosystem II – chlorophyll a P680
 Blue and red are most absorbed, and green is least absorbed (most reflected) giving a
green colour